Alexander Olegovich Kaun (in Russian: Александр Олегович Каун, pronounced Kahn, born May 8, 1985, in Tomsk, Russian SFSR, Soviet Union) is a Russian professional basketball player. He played college basketball in the United States with the University of Kansas for four seasons, including the 2007–2008 national championship team. He was drafted in the second round of the 2008 NBA Draft by the Seattle SuperSonics, with the 56th overall pick. His draft rights were then traded to the Cleveland Cavaliers for cash considerations. He is currently with CSKA Moscow.

In high school at the Florida Air Academy, Kaun averaged 13.0 points, 7.0 rebounds and 2.0 blocks per game as a junior and 15.3 points and 12.6 rebounds per game as a senior. He led his team to a 23-0 record and to the Florida state championships. During the fall of 2003, he elected to play college basketball for Bill Self at the University of Kansas. Duke and Michigan State also recruited him heavily.

During his freshman season with the Kansas Jayhawks, he played in 27 games, starting twice. In his sophomore season he helped the Jayhawks to an 80-68 win against the Texas Longhorns, which made the Jayhawks the 2006 Big 12 Conference champions. During his senior year, he was the back-up center for the Jayhawks and with them he won the 2008 NCAA Championship. He graduated with a degree in computer science and was selected to the Academic All Big 12 Basketball Team three times, in 2006, 2007, and 2008.